Electrical grounding terminal



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1970 F. J. MALTAIS ETAL ELECTRICAL enoumnme TERMINAL 3 SheetS -Shet 3Filed larl'lv 8 1968 INYENTUk FlumlcK JEMu MILTAIS wmnew wnuv LOOSE Maw5 ML United States Patent O 3,535,673 ELECTRICAL GROUNDING TERMINALFrederick Jean Maltais, Camp Hill, and Winfield Warren Loose, Reading,Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Filed Mar. 8, 1968, Ser. No. 711,694 Int. Cl. H01r 13/34 US. Cl. 339-95Claims ABSTRACT OF THE DISCLOSURE An electrical grounding terminal hasleg members provided with serrations thereon for cleaning a hole in ametal member in which the terminal is forcefully driven to provide anexcellent electrical connection therebetween and for securing theterminal in the hole.

This invention relates to electrical terminals and more particularly toelectrical grounding terminals for connection with grounding planes orthe like.

In a number of fields, ground connections are necessary and these areformed in various ways. One way is the soldering of a wire to a groundplane. Another way consists of wrapping the end of a wire around a screwor bolt on a ground plane and tightening the screw or bolt. A furtherway involves applying a terminal to an end of a wire and securing theterminal to a ground plane via a screw or bolt.

These approaches are time consuming and are not reliable in that a coldsolder joint could result and the screws or bolts could work loosethereby resulting in an improper ground connection. The areas for theground connection may be dirty which would create problems withcontinuity and the connection may be impaired due to the presence ofoxide coatings.

An object of the present invention is to provide a grounding terminalwhich overcomes the drawbacks of the prior art devices.

Another object of the invention is the provision of a grounding terminalwhich is easily terminated in a ground plane.

A further object of the invention is the provision of a groundingterminal that cleans the area in which the termination is to be effectedduring the making of the termination.

An additional object of the invention is to provide a grounding terminalthat is locked in position.

A still further object of the invention is the provision of a groundingterminal that exerts positive retention pressure at all times once ithas been driven into a ground plane.

Still an additional object of the invention is to provide a groundingterminal having stop means to prevent over insertion of the groundingterminal in a ground plane.

A still additional object of the invention is the provision of agrounding terminal having staggered teeth means to accommodate variousthicknesses of ground planes.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the invention but aregiven for purposes of illustration in order that others skilled in theart may fully understand the invention and the principles thereof andthe manner of applying it in practical use so that they may modify it invarious forms, each as may be best suited to the conditions of aparticular use.

In the drawings:

FIG. 1 is a perspective exploded view of a grounding plane and agrounding terminal exploded therefrom;

FIG. 2 is a cross-sectional view of the grounding section of thegrounding terminal;

FIG. 3 is a top plan view of the grounding section of the groundingterminal;

FIG. 4 is a view of the grounding terminal prior to being driven intoposition in the grounding plane;

FIG. 5 is a view similar to FIG. 4- with the grounding terminal inposition in the grounding plane;

FIG. 6 is a view taken along lines 6-6 of FIG. 5;

FIG. 7 is a cross-sectional view of an alternative embodiment of thegrounding terminal;

FIG. 8 is a perspective exploded view of a further embodiment of thegrounding terminal exploded from a grounding plane;

FIG. 9 is an exploded view of the grounding terminal of FIG. 8 prior tobeing driven into the grounding plane;

FIG. 10 is a view similar to FIG. 9 with the grounding terminal inposition in the grounding plane;

FIG. 11 is a view taken along lines 11-11 of FIG. 10;

FIG. 12 is a view taken along lines 12-12 of FIG. 10;

FIG. 13 is a perspective view of a further embodiment of the groundingterminal;

FIG. 14 is a side elevational view of FIG. 13;

FIG. 15 is an exploded view of the grounding terminal of FIG. 13 priorto being driven into position in a ground plane;

FIG. 16 is a view similar to FIG. 15 with the grounding terminal driveninto position in the grounding plane;

FIG. 17 is a top plan view of an additional embodiment of the groundingterminal;

FIG. 18 is an end view of FIG. 17 looking from the left toward theright;

FIG. 19 is a side elevational view of FIG. 17;

FIG. 20 is a view taken along lines 20-20 of FIG. 19; and

FIG. 21 illustrates the embodiment of FIGS. 17 through 20 being used asa fastener.

Turning now to the drawings and especially FIGS. 1 through 6, agrounding terminal GT comprises legs 1 and 2 which are connectedtogether by a split tapered body 3, legs 1 and 2 being appendagesextending outwardly from the opposing edges of the split. Saw toothserrations 4 are provided along legs 1 and 2 and projections 5 areprovided in the body 3 opposite the inner ends of the serrated areas ofthe legs. An outwardly-directed protrusion 6 is formed in body 3adjacent projections 5. Wings 7 extend outwardly substantially at rightangles from the large end of body 3 as well as a shank portion 8 whichterminates in a ferrule section 9 for engagement with the wire andinsulation of conductor means (not shown) to be secured therein viaconventional crimping techniques.

In use, grounding terminal GT is forcefully driven into an aperture 10of a grounding plane 11 which is generally of sheet metal. Wings 7 serveas a driving surface against which a hammer or like instrument isapplied to drive the grounding terminal in position. Of course, wings 7need not be present since the large edge can be engaged by the drivingmeans. Legs 1 and 2 are directed away from each other, as illustrated inFIG. 3, so that they are springably moved toward each other when body 3is driven into aperture 10. Tapered body 3 wedgingly secures thegrounding terminal in position along with serrations 4 and theconfiguration of serrations 4 is such that they facilitate driving theterminal in the aperture but they prevent the grounding terminal frombacking out of aperture 10 once it has been driven thereinto.

Projections define stabilizing means to stabilize body 3 in aperture andprotrusion 6 acts as a stop means to limit the movement of body 3 intogrounding plane 11. Of course, protrusion 6 can be eliminated and wings7 can serve as stop means. The spring characteristics of the body 3provides constant spring pressure to legs 1 and .2 so that a constantretaining force is present at all times. Serrations 4 not only lock body3 in position in grounding plane 11 but they also clean the area ofcontact so that good electrical conductivity is established. Body 3 canbe driven into various thicknesses of grounding planes as a result ofits tapered configuration. Grounding terminal GT can be driven into agrounding plane without the application of special tooling or by anunskilled laborer and without preparing the ground plane to clean thearea in which the connection is to be made.

It should be noted that protrusion 6 need not be provided in body 3 topermit further insertion of the body into the sheet metal panel if suchis necessary because serrations 4 can be provided along the lengths oflegs 1 and 2. Also, because of the reduction in diameter and thecompression of body 3 when inserted into the grounding plane, thegrounding wire could be inserted into the grounding plane, the groundingwire could be inserted in aperture 10 prior to grounding terminal GTbeing driven in position therein thereby obviating the necessity forshank portion 8 and the ferrule section 9. The serrations on one legmember can be axially spaced relative to the serrations or the other legmember so that the serrations can bite into the grounding plane ataxially-spaced locations.

FIG. 7 illustrates grounding terminal GTa which is an alternativeembodiment of grounding terminal GT. Grounding terminal GTa. is similarin every respect to grounding terminal GT except that no stabilizingprojections are provided on body 341 although they can be providedthereon and protrusion 6 is replaced with an opening 12 while the legsare provided with extensions 13. Opening 12 and extensions 13 definestop means to limit the movement of body 3a within opening 19 ofgrounding plane 11.

FIGS. 8 through 12 illustrate grounding terminal GTb which is a furtherembodiment of the invention. Grounding terminal GTb includes a base 14from which shank portion extends for connection to an electricalconductor means and oppositely disposed leg members 16. Base 14 definesa body connecting the leg members together. As can be discerned, legmembers 16 are V-shaped with the bases of the VS being directed towardeach other and serrations 1'7 are provided along each of the taperededges of leg member 16. Recesses 18 are located at the inner ends ofserrations 17 to provide stop means to limit the movement of thegrounding terminal in ground plane 11. Since leg members 16 have aV-shaped configuration, spring pressure is obtained when pressure isapplied to the two edges thereof when forcefully driven in aperture 10of grounding plane 11. Serrations 17 are angles so as to permit easyinsertion when installed and they lock the grounding terminal inposition. Serrations 17 are preferably staggered to provide a firmtermination and retention in various sheet metal thicknesses.

As the ground terminal is forcefully driven into aperture 10 ofgrounding plane 11 via the application of the force-driving member suchas a hammer or the like against base 14, legs 16 perform as V-shapedsprings thereby obtaining resilient action via the springcharacteristics of the legs thereby maintaining constant pressure of theterminal against the grounding plane. The legs are shaped andproportioned so that pairs of serrations may be deflected toward thecenter of the aperture a certain amount and no further to assurebroaching action.

FIGS. 13 through 16 illustrate grounding terminal GTc which is similarin construction in every detail to grounding terminal GT1] except thatbase 14a has an outwardly directed arcuate configuration and an oblongopening 19 therein. Arcuate base 14a, upon being forcefully hit by ahammer to drive grounding terminal GTc into aperture 10 of groundingplane 11, is deformed causing leg members 16a to be spread outwardly inaperture 10 thereby applying outwardly-directed forces on the legmembers to more effectively secure the terminal in the grounding plane.Opening 19 provides a weakened area of base 14a so that base 14a canreadily assume a substantially flat configuration after being driveninto grounding plane 11 as illustrated in FIG. 16.

FIGS. 17 through 2.1 illustrate grounding terminal GTd which is anadditional embodiment of the invention. Grounding terminal GTd isprovided with a central planar section 20 from which arcuate-shaped legmembers 21 extend. Section 26 defines a body connecting the leg memberstogether. Leg members 21 extend outwardly from planar section 20 in sucha manner that the combination of planar section 20 and leg members 21form an S-shaped configuration in cross section as illustrated in FIG.20. Leading edges 22 of leg members 21 are tapered to facilitate theinsertion of the grounding terminal in position in an aperture of agrounding plane. The trailing ends of leg members 21 are bentsubstantially at right angles to form wings 23 to provide force-drivingsurfaces against which a force-driving member engages to drive aterminal into position in a grounding plane. One of wings 23 can beprovided with a shank portion and ferrule section for securing onto anelectrical conductor means.

Outwardly extending projections or serrations 24 are formed in legmembers 21 and they are disposed at a slight angle with respect to thelongitudinal axis of the terminal. Projections 24- in the leg members 21are arranged such that the terminal can be threaded out of engagementwith a grounding plane by insertion of a screwdriver in space 25. TheS-shaped configuration of the body of the grounding terminal appliesconstant pressure onto a grounding plane once the terminal has beenforcefully driven thereinto.

As illustrated in FIG. 21, the embodiment of FIGS. 17 through 20 can beused as a fastener to fasten two members 26 and 27 together with member26 being plastic or other flowable structural material. The fastener ofFIG. 21 is forcefully driven into openings 28 and 29 of mem bers 25 and27 with projections 24 biting into and flowing therearound to maintainthe fastener secured in position therein. Wings 23 engage member 27thereby securely fastening members 26 and 27 together. A screwdriver canbe inserted into space 25 to threadably remove the fastener from member26 thereby unfastening members 26 and 27. The fastener can also bethreadably reinserted since projections 24 provide a self-threadingfeature. The springable characteristics of leg members 21 apply constantpressure against the Wall of opening 28 thereby securing the fastener inposition therein.

It should also be noted that wings 23 are slightly bent toward the frontend of the body so as to provide a resilient clamping force onto member27. This feature abets the retaining characteristics and toleratesvibration and shock environments better than conventional solidthreadedfasteners or the like.

The embodiments described hereinabove are susceptible to mass productionby automatic machinery and they are conveniently formed by shaping asheet metal blank or strip of a suitable electrically conductive metalin successive forming steps. The metal is sufficiently hard andresilient to impart to the connection area a springlike character, yetit is sufliciently malleable to permit cold-forging or crimping of theferrule section onto a conductor means to provide an excellentelectrical and mechanical connection. The spring characteristics of themetal are such that the terminals apply constant compressive pressureonto the area in which they are forcefully driven.

It will, therefore, be appreciated that the aforementioned and otherdesirable objects have been achieved; however, it should be emphasizedthat the particular embodiments of the invention, which are shown anddescribed herein, are intended as merely illustrative and not asrestrictive of the invention.

The invention is claimed in accordance with the following:

1. An electrical grounding terminal adapted to be forcefully driven intoa hole of a grounding plane comprising a base member, leg membersextending outwardly from opposite edges of said base member in the samedirection opposite each other and being freely movable toward and awayfrom each other, said leg members having a V- shape in cross sectionalong a length thereof but terminating short of the junctures of saidleg members with said base member, said leg members being tapered fromfree ends thereof to a position adjacent said base member with thesmallest dimension being at the free ends, and each edge of said legmembers having serrations therealong defining teeth.

2. An electrical grounding terminal according to claim 1 wherein saidbase member has a substantially flat configuration prior to being driveninto the ground plane hole.

3. An electrical grounding terminal according to claim 1 wherein saidbase member has an arcuate configuration prior to being driven into theground plane hole and which, upon being engaged by a force-drivingmember to drive said terminal in the ground plane hole, assumes a flatconfiguration thereby applying outwardly directed pressure on the legmembers adjacent said base member.

4. An electrical grounding terminal according to claim 1 wherein saidleg members have recesses at inner ends of said serrations defining stopmeans limiting the movement of said leg members into the ground planehole when said grounding terminal is forcefully driven there- 5. Anelectrical grounding terminal according to claim 1 wherein saidserrations along each leg member edge are staggered relative to theserrations on the opposite leg member edge of each leg member.

6. An electrical grounding terminal comprising a base member, legmembers extending outwardly from opposite edges of said base member inthe same direction opposite each other and having free ends, said legmembers having inner and outer sections, said inner sections having asubstantially rectangular configuration, said outer sections having aV-shaped configuration with bases thereof directed inwardly, edges ofsaid outer sections being tapered from said free ends to said innersections, and each of said edges of said outer sections havingserrations therealong defining teeth.

7. An electrical grounding terminal according to claim 6 wherein saidinner sections have portions at inner ends of said outer sections whichextend outwardly beyond the corresponding serrated edges of said outersections thereby defining stop means to limit movement of said terminalin a hole of a grounding plane.

8. An electrical grounding terminal according to claim 6 wherein saidserrations along one edge of one of said V-shaped outer sections arestaggered with respect to the serrations along the other edge of thesaid one of said V-shaped outer sections.

9. An electrical grounding terminal according to claim 6 wherein saidbase member has a substantially flat configuration.

10. An electrical grounding terminal according to claim 6 wherein saidbase member has a shank section extending outwardly therefrom, saidshank section having ferrule means thereon for connection to electricalconductor means.

References Cited UNITED STATES PATENTS 2,077,120 4/1937 Lombard 24-2132,128,005 8/1938 Lombard -5 2,138,195 11/1938 Place 85-5 2,391,29812/1945 Davis 85-5 2,560,961 7/1951 Knohl 151-4175 2,852,829 9/1958Holton et al.

3,068,540 12/1962 Jaworski 24-73 MARVIN A. CHAMPION, Primary Examiner I.H. McGLYNN, Assistant Examiner US. Cl. X.R. 24-73; 339-14

